I have never been to an American wedding before. I (female) am going as my boyfriend’s plus one to a wedding he was invited to. It is an evening event and the dress code is Black Tie, so I am working mindfully to match the dress code. What other etiquette should I keep in mind? Should I offer to split on the gift? Are there any other details I should pay attention to?

my husband and I got married over the weekend and the moment I woke up the next day, I felt extremely anxious about how the day went. the weather was overall gorgeous, I was obsessed with our venue, and I felt like a princess. but, the day was way too intense for me, it was very rushed and went by extremely fast, which a lot of people warned me would happen. I didn’t get many photos with my husband’s parents or my brothers, my mom said she didn’t get any photos with her and my dad, people kept asking me questions all day, and whenever things went south (which a lot did, unfortunately) it was my job to try to correct it even though my brain was fried at that point.
idk I’m very grateful to have married the life of my life and everyone keeps telling me how much fun they had, but I wish I could have enjoyed myself more. I hardly ate anything because I was so nervous and all over the place all day, which I’m very upset about because the food was some of the best I’ve ever tasted (we did take home some leftovers though, thankfully). there’s so much I wish I did differently but I was so overwhelmed in the moment, I forgot a lot of the ideas I had, and I wish the people in my life would have stepped up to help me with the logistics more.
I’m having such a hard time calming down and finally taking the time to relax after my wedding day, did anyone else feel this way about their wedding?